What does a yellow light mean?

A yellow light signals to drivers that the traffic light is about to change to red, indicating that they should prepare to stop if it is safe to do so. This gives drivers a chance to react appropriately rather than abruptly stopping in the intersection, which can lead to accidents. The purpose of the yellow light is to enhance safety by alerting drivers to anticipate a change in traffic direction, allowing them to slow down and prepare to stop or, if they are already too close to the intersection to stop safely, to proceed with caution.

In contrast, the options that suggest either speeding up or proceeding with caution are not appropriate responses to a yellow light, as this could lead to increased risk of an accident. The yellow light is not a warning to slow down without the context of stopping; rather, it explicitly prepares drivers for a stop while considering their position and safety on the road.